The objective of this project is to provide a model for the investigation of developmental and perhaps permanent functional abnormalities expressed in the lung, liver or kidney which may arise from perinatal exposure to pesticides, environmental agents, environmental stress or drugs, or from interactions between such exposures during gestation or neonatal development. Inherent in this objective is the assumption that susceptibility to chemical and nonchemical stresses of developing organ systems may be present throughout the entire perinatal period, and thus exposures will be made throughout as well as at discrete times during development; and secondly that the affects of such stresses may be subtle enough to escape detection by classical teratologic techniques yet may still impair the developing organism. The herbicides dinoseb, paraquat, diquat and morfamquat and the environmental contaminants, mercury, lead, and 2,3,7,8-tetrachlorodibenzo-p-dioxin will be among the agents investigated. Pregnant mice or rats will be treated with one or the other of the test agents either throughout gestation period when the organ systems are differentiating or growing. Other animals will be exposed at birth or during the neonatal period. The effect of such treatments on young animals at various ages will be determined by examining various parameters of organ system function. In particular the function of the lung, liver and kidney as organs of drug metabolism or excretion will be determined. Organic ion transport, sugar transport, water and electrolyte balance, biliary excretion and oxygen sensitivity are among the variables to be examined. Functional changes will be correlated with histologic development.